During the last few years there has been an extraordinary development of computer aided tools intended
to present or communicate the results of architectural projects. But there has not been a comparable
progress in the development of tools intended to assist design to generate architectural forms in an easy
and interactive way. Even worst, architects who use the powerful means provided by computers, as a
direct tool to create architectural forms are still an exception. Architecture continues to be produced by
traditional means using the computer as little more than a drafting tool.

The main reasons that may explain this situation can be identified rather easily, although there will be
significant differences of opinion. Mine is that it is a mistake trying to advance too rapidly and, for
instance, propose integrated design methods using expert systems and artificial intelligence resources
when do not have still an adequate tool to generate and modify simple 3D models.

The modelling tools we have at the present moment are clearly unsatisfactory. Their principal limitation is
the lack of appropriate instruments to modify interactively the model once it has been created. This is a
fundamental aspect in any design activity, where the designer is constantly going forward and
backwards, reelaborating once and again some particular aspect of the model, or its general layout, or
even coming back to a previous solution that had been temporarily abandoned.